Вas M. O., and S. P. Lavrenyuk. “On the Uniqueness of a Solution of the Fourier Problem for a System of Sobolev-gal’pern Type”. Ukrains’kyi Matematychnyi Zhurnal 48, no. 1 (January 25, 1996): 124–128. Accessed December 6, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/5370.